424 PATHOGENIC BACTERIA. gelatin punctures there is no liquefaction. The growth takes place upon the surface principally, where a grayish- white mass slowly forms. Upon agar-agar a grayish-white development devoid of peculiarities occurs. Upon potato a rather thin whitish growth may be observed after a few days. The bacillus grows well in milk, with the production of an acid reaction, but without coagulation. The organism is pathogenic for mice of all kinds, which succumb in from one to two days when inoculated subcutaneously, and in eight to ten or twelve days when fed upon material containing the bacillus. The bacilli multiply rapidly in the blood- and lymph-channels, and cause death from a general septicemia. Loffler expressed the opinion that this bacillus might be of use in ridding infested premises of mice, and the results of its use for this purpose have been highly satis- factory. He has succeeded in ridding a field so infested as to be useless for agricultural purposes by saturating some bread with bouillon cultures of the bacillus and distributing it near the holes inhabited by the mice. The bacilli that were eaten by the mice not only killed them, but also infected others which ate the dead bodies of the first victims, and so the extermination progressed until scarcely a mouse remained in the field. In discuss- ing the practical applicability of the employment of cul- tures of this bacillus for the destruction of field-mice, Brunner1 calls attention to certain conditions that are requisite for a satisfactory result, (i) It is necessary, first of all, to attack rather extensive areas of the invaded territory, and not to attempt to destroy the mice of a small field into which an indefinite number of fresh animals may immediately come from the surrounding fields. The country-people, who are the sufferers, should combine their efforts so as to extend the benefits widely. (2) The preparation of the cultures is a matter of im- 1 Centralbl.f. Bakt. u Parasitenk., Jan. 19, 1898, Bd. xxiii., No. 2.